Herbert H. Ross

“ There are many small animals that belong to the same general group as insects and that are frequently collected with them. Spiders, centipedes, and amphipods are a few of many examples of such animals. Together with insects, they form the animal phylum called Arthropoda, characterized by having segmented bodies and jointed legs. A brief description is included here of the common groups of these insect relatives found in Illinois. ”

“ In late fall and winter, sifting provides one of the most profitable types of collecting; in any season, it will turn up such things as rare spiders and beetles. Sifting is most successful for finding large, active insects. For small, slow-moving forms, Berlese funnels offer a better collecting method.
Berlese Funnel
When you are wandering through woods or fields, do you realize that you are stepping on more insects than you ever see? The ground cover and soil are inhabited by a vast assemblage of little animals that are seldom seen by the casual collector. ”

“ When the insect resumes its normal activities immediately after a molt, the soft parts of the cuticle fall into a large number of pleats or folds between the hard parts. As the insect grows larger following a molt, the body can lengthen by the unfolding of these pleated areas.
The stages of the insect between molts are called instars. Among the different orders of insects the number of instars in the life history may vary, and various instars may have different forms. These characteristics of molting and instars are therefore important items in the classification of insects. ”

“ In this and in the following orders of insects, the life history includes four distinct stages, the egg, the larva, the pupa, and the adult. In the Megaloptera, which include alderflies and dobsonflies, the larvae are caterpillar-like or grublike, and the pupae represent a transformation stage in which the tissues of the larvae are converted to those of the adults. The larvae never have external wing pads; in winged species, these pads first appear externally in the pupae. The adults have long antennae, two similar pairs of net-veined wings, and chewing mouthparts. ”

“ The adult flies have very long front legs, short antennae, practically no mouthparts, usually two pairs of wings, and two or three long tails. When a mayfly is at rest, the wings are held together above the body. Hexagenia limbata (Serville) , figs. 26 and 27, is one of the very common Illinois mayflies and is an important factor in the food economy of many fish.
Mayflies, formerly called Plectoptera, together with stoneflies, caddisflies, and midges, constitute a very large portion of the life of our lakes and streams; all four groups are important as fish food. ”

“ If aquatic insects are on the wing, they will come to the light and eventually drop in the fluid, which traps them. With a small piece of wet cardboard, you can scrape the entire insect contents of the pan into a small bottle of alcohol, which you should then label, giving date, name of collector, and location. ”

“ Measured by geological time, insects are among the oldest of land animals, having first evolved from an earlier, centipede-like ancestor about 400 million years ago. The first insects had no wings and differed from the many-legged centipede-like creatures of that time chiefly in having only three pairs of functional legs. The legs were situated on the three segments immediately behind the head; the three distinctive segments are together called the thorax. The part of the body behind the thorax is called the abdomen. ”

“ Collecting equipment, including an aspirator, camel’s-hair brush, forceps, vials, and killing bottle.
Material such as leaf mold is placed in the sieve and this is shaken over the white oilcloth, which has been spread on a level spot on the ground. The small insects fall on the cloth and can be picked up with the aspirator or the camel’s-hair brush. Many insects feign death when they fall to the oilcloth and they are difficult to detect in the bits of sifted material until they “revive” and start to move. ”

“ Remember that some insects build cases in which they hide when disturbed. It takes a practiced eye to see a motionless case. After an insect has dried out a little, it partially emerges from the case and drags it along in search of water ”

“ Most insects caught in a net while it is wet are unfit for a collection.
Flowers, herbs, and boughs should be swept with a sidewise motion. A sidewise sweep will collect more insects than an upward or downward sweep and at the same time mutilate less. If care is taken not to damage flowers or foliage, the same patch of plants may be visited several times with profit. The contents of the bag should be removed after every few sweeps or strokes. This practice will prevent damage to the insects caused by being jostled about in the net with a large amount of debris. ”

“ Certain items placed in the funnel may produce distinctive and unusual catches. Recently deserted birds’ nests will give mites and, frequently, rare beetles, flies, and their larvae; mature or overmature mushrooms and bracket fungi are often rich in beetles, thrips, and maggots; bark of living trees may produce unusual thrips, springtails, and psocids; debris from aquatic habitats and from the wet edges of ponds and tiny streams may be productive of rare aquatic and semiaquatic forms. Moss is a good source of peculiar species of springtails, thrips, and beetles ”

“ In Illinois the only poisonous species of any importance are the black widow spider, which is found in a variety of situations, and the recluse spider, Loxosceles reclusa Gertsch & Mulaik, which has been found in house basements in southern Illinois. ”

“ Within the groups, individuals with smaller wings were favored; they survived and reproduced in greater numbers than other individuals. Over many generations then, the wings in some groups became very small or were entirely lost. Sometimes this loss of wings occurred in all the adult forms, as in the fleas. Individuals of only one sex may be wingless, as are the females of two Illinois moths, one of which produces bagworms and the other cankerworms. In two groups, the termites and the ants, a wingless worker or soldier caste is produced ”

“ In late spring, in summer, and in early fall, insects are very abundant in fields and woods, and large numbers of them may be caught by sweeping through the grass and branches with a strong insect net. Flowers of all descriptions are favorite visiting places of many bees, flies, beetles, and other insects, and will afford good collecting. ”

“ Swarms of aquatic insects come to street lights of towns along rivers, sometimes in such numbers as to pile up in a crawling mass under each light. Collecting at this source is best on warm, cloudy nights; wind or cold keeps most nocturnal insects fairly inactive. Different species of moths and beetles visit the lights in different seasons so that collecting by this method alone yields many kinds of insects. ”

“ Great care must be taken that sufficient cellucotton is put in the box to take up all moisture in the insect bodies. If the specimens are large, they should be allowed to dry moderately uncovered before being placed in cellucotton in storage containers. If insects become damp in the containers they quickly mold or rot. The containers 19 should be wood or cardboard boxes, for they will not sweat, as will a metal box. The insects should be packed tightly enough to prevent their rolling around and breaking. ”

“ Patience is required to get the best results with the sifter, which provides one of the best methods for winter collecting.
To use the cyanide cork with the vial aspirator shown in fig. 4, simply exchange the corks. If the glass tube aspirator is used, plug 12 the intake tube, 5c, with a tapered paper plug or a leaf, jar the insects away from the stopper at the opposite end, remove this stopper cautiously, and quickly insert in its place the cyanide cork. When the specimens are stupefied, they may be transferred to another bottle. ”

“ From either standing stumps or fallen logs in which the wood is still too hard to break up, collect the loose bark, as it is often quite productive. Frequently, if you roll a log over, you may find animal runs under it; the debris and earth under and around these runs, together with animal nests, frequently give unusual catches, such as larvae and adults of fleas and rare ticks. Especially productive are samples taken from the interior of a standing hollow tree; from the bottom of the hollow you can scoop out a foot or more of fine, rotten, woody material rich in rare insects. ”

“ If an electric light is used for heating, it should be hung directly over the center of the funnel, no cloth should be tied over the top, and the light should have a reflector nearly as wide as the top of the funnel. ”

“ Never test the strength of a killing bottle by taking the cork out and smelling the contents. As an added precaution and safeguard to the collector, tape the bottom of the cyanide bottle to protect it against breakage. ”

“ Small, wingless, fragile, blind, whitish insects that run fairly rapidly. They have long antennae and either two fairly long tails or a pair of forceps-like structures at the end of the abdomen. They are terrestrial and are found chiefly under stones in humid and shady situations. Fig. 21 shows a common campodeid, a species of Campodea, occurring commonly in Illinois. ”

“ Bees, Wasps, Ants, Sawflies
Insects typically with two pairs of wings; antennae of various lengths; chewing mouthparts; without tails. A typical member of this group is the wasp Vespula maculata (Linnaeus) , fig. 56. Many adult members of the group are atypical in that they lack wings; these include all the true ants, fig. 57, which are without wings except for the sexual forms produced at the time of the nuptial flights. Forms of one species, Lasius interjectus Mayr, are shown in fig. 58. The wings, when developed, are without scales; the venation is much less extensive than in the Neuroptera ”

“ Springtails
Small, wingless insects that jump and crawl when disturbed. They have short antennae and usually a springing structure on the under side near the posterior end of the body. They live in moist places and are abundant under leaf mold and similar material. Illustrated in fig. 23 is Achorutes armatus Nicolet, which often becomes a major pest in mushroom cellars and greenhouses.
About a hundred different species of Collembola occur in Illinois; they include some of our smallest insects. A few never grow longer than 0.007 inch ”

“ It is estimated that there are about 20,000 different species of insects in Illinois and 150,000 in North America. The collection contains representatives of over 15,000 Illinois species, and a great many other North American species useful as comparison material in the identification of Illinois forms. ”

“ The Illinois fauna thus contains a remarkable variety of insects, including forms such as the bristletails, mayflies, and cockroaches, which are practically “living fossils” of insects that lived hundreds of millions of years ago.
Primitive Wingless Insects
Only five orders of primitive wingless insects are known; species of each order occur in Illinois. These orders represent the stages in insect evolution before wings had appeared.
Fig. 21.—Diplura. A campodeid belonging to the genus Campodea, found under stones in moist places. Actual length of adult about 0.1 inch. ”

“ Several satisfactory types of boxes for housing insect specimens may be bought from commercial supply companies. These are usually much better than boxes of home construction, being more nearly dustproof and pestproof. ”

“ Corrodentia eat fungus growth on bark, dead leaves, moldy grain, damp books, and similar materials. Some of the outdoor species become very abundant on drying corn leaves during autumn and may breed in immense numbers. They do little harm, feeding chiefly on fungus strands. ”

“ Fragile or soft insects with chewing mouthparts. The mating forms are dark brown and have two similar pairs of wings; both pairs are delicate and have a fine network of veins. The workers are white and soft bodied. Termites, which live in colonies in wood, are also called “white ants,” although they are not true ants. The common native species in Illinois is Reticulitermes flavipes (Kollar) , fig. 33, which lives in rotten logs and is destructive to buildings of wooden construction throughout Illinois; it is most destructive in the southern part of the state. ”

“ The young of these insects are somewhat similar to the adults but are softer 48 bodied. Fig. 43 shows an adult of Thrips tabaci Lindeman, the onion thrips. Thrips suck the juice from plants. Because of their minute size, they are seldom noticed, but they can be collected in large numbers from blossoms of almost any plant. A few species of thrips, such as the onion thrips and the privet thrips, attack agricultural or horticultural plants and inflict considerable damage. A few species occasionally bite human beings. ”

“ Insects with only one pair of wings, each wing with a limited number of veins. Other characters of the order, including antennae and mouthparts, are extremely varied. Most immature stages are wormlike or maggot-like. They live in protected situations, such as within the tissues of a plant, in water, in leaf mold, or in the tissues of animals. A typical life cycle is that shown for the house fly, Musca domestica Linnaeus, fig. ”

“ Most adult insects in collections are mounted on pins. Most medium-sized to large insects, such as grasshoppers, butterflies, moths, flies, bees, and many beetles should be pinned directly through the body from top to bottom. Many small insects, such as leafhoppers, plant bugs, small beetles, and the like, should be glued on card points. Immature insects and the adults of some groups are best preserved in fluid. ”